1. Field of the Invention
The invention relates to a device for the blending of different fibres in a desired ratio of components, especially for the production of envelopes for drain pipes.
2. Description of Prior Art
It is known, to use different kind of fibres for envelopes of drain pipes, for example straw, coconut fibres, polypropylene fibres or such like. According to the sort of soil a desired fibre is used. As known straw rots relatively quickly. Coconut fibres rot too, but this takes a longer time. Polypropylene fibres do not rot at all. In this connection it is also known to build up an envelope layer of underlayers of different fibres, to obtain desired filter properties.